John muir



No. 625,407. Patented may 23', |899. J. Mum.

LEATHER TIRE FDR WHEELS.

(Application led Nov. 14, 1898.)

(No Model.)

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UNITED STATES PATENT OFFICE.

JOHN MUIR, OF BEITH, SCOTLAND.

LEATHER TIRE FOR WHEELS.

SPECIFICATION forming part of Letters Patent No. 625,407, dated May 23, 1899.

Application filed November 14,1898. Serial No. 696,437.v ,(No model.) v

T0 all wtorn if; may concern.-

Be it known that I, JOHN MUIR, a subjectV of the Queen of Great Britain, residing at Mains I'Iouse, Beith, in the county of Ayr, Scotland, have invented a new and useful Improvement in Leather Tires for Wheels, (for which I have applied for provisionalprotection in Great Britain, No. 8,952, bearing dat-e April 1S, 1898,) of which the following is a specification.

My invention relates to an improvement in the tires of what are known as leather-shod wheels.

The idea of employing leather as a material for the tire or periphery of a wheel is well known, and leather has been used in this way both in one or more layers around the periphery of the wheel or in sections placed side by side within asocket-rim, so that its edge alone forms the wearing-surface of the tire; but such a tire as hitherto constructed possesses serious drawbacks and has not proved itself sufficiently durable in wear. The reason of this lack of durability consists, essentially, in the want of a suitably-prepared leather for the purpose. Ordinaryleather tanned in the usual manner may be compared to a bundle of loosely-connected ibers having a large capacity for absorbing moisture and if subjected to extreme pressure, as is usual in the construction of the tire, very materially suffers from disintegration and crushing of the fibers, whereby the liability to Wear at the edge is still further increased. Such a wheel shod in this manner rapidly absorbs moisture, which swollen leather may even split the socket or rim, and in any case the softened leather wears away rapidly in contact with the ground. The reason of this want of durability is, primarily,in the selection of an unsuitable kind of leather, and, secondly, in the treatment to which this leather has been eX- posed during the tanning process.

An examination of ordinary leather makes it evident that natures plan of construction of the ordinary original hide is to build up a great number of small interlacing ibers which are held together by a cement-like substance. In the ordinary processof tanning, lime by its swelling and caustic action dissolves this cement-like substance and weakens and disintegrates those small bers. The object of this lime process is to make room for tan and heavy-weighing substances in order to produce commercial leather which will weigh well. Then, again, the great pressure employed by the circumferential-pressure machine (used to produce a solid wheel which will resist indentation from road metal, &c., and keep the wheel partially impervious to water) further crushes and very much disintegrates these interlaced fibers in ordinary commercial leather, so that when it is exposed in the wheel to the severe wear ot' vehicular traffic the leather easily grinds away, having been really specially prepared to easily do so, first, by the caustic action of the lime, and, secondly, by the further bruising of the already weakened bers by compression. NOW I have discovered that the skin of the pig is the substance most suited for the purpose in view. Pigskin diiers from other hides ordinarily known in commerce in that it is formed, essentially, of adense and practically homogeneous mass of almost horn-like substance and not ibrous in its nature as the skins of other domestic animals commonly used for the preparation of leather. Moreover, it possesses When treated as I propose a greater flexibility because supplied naturally with oily, gelatinous, and albuminous matter and is therefore by nature eminently suited to resist attrition wear. This natural advantage of pigskin may be greatly preserved and enhanced by proper preparation for the purpose in View. Instead of soaking the hide in the lime-pit, as usual, until the bristles are removed by the action of the lime and the commencement of putrefaction, thus submitting it to a caustic and putrefactive action destructive of those oily, gelatinous, and albuminous7 ingredients, I remove the upper part of the bristles by mechanical means and then by means of a suitable reagent-such, for instance, as a sulfid of calcium or of barium or by means of sulid of lime or tankwaste or any other suitable substance of an acid or alkaline nature- I complete this substituted process for the ordinary depilatory one. The result of this treatment is to leave the roots of the bristles in the hide, thus adding greatly to the flexibility of the leather after compression and to its imperviousness,

IDO

because the bristles in pigskin are deep set,

and their removal in the ordinary manner leaves a considerable aperture in the skin, which in my process remains closed by leaving the root in it, which root is the strongest part of the bristle.

I may altogether dispense with the liming process commonly used or I may employ the same to a limited extent for the purpose of somewhat swellin g the hide, care being taken not to cause the bristles to fall out or to use so much ,lime as to burn and destroy the naturally strong bristle or disintegrate and make the pigskin less homogeneous.

The antiseptic action of the lime, if used moderately, usefully swells the hide and preserves the bristle-roots from the alkaline action of the otheringred'rents used. I may also employ any known substance-such as salt or alum, formaldehyde, or an acid-in addition to the aforesaid process, which will assist in improving or fixing the oily, gelatinous, or

' albuminous ingredients and secure the bristles more permanently in the skin. The hide is then further tanned by any suitable chemical process, preferably such, for instance, as that known as the Chrome process, or I may employ other tanning materials. After the tanning process is completed I may further treat the hide with a filling or waterproof substance. For this purpose l may use rubber or any suitable rubber substitute or composition, or artificial or mineral wax, or any suitable oleaginous substance or Waterproof compound, or I may add, without incorporation, such substances as will give increased flexibility to the pigskin, this being the most porous of all leather and therefore most suitable for this treatment. The filling' substance may be applied in solution, the solvent being afterward removed by evaporation, or the filling substance may be forced into the leather by pressure or otherwise applied. rIhe leather thus prepared is cut into pieces of the required size and shape and placed in or around the tire, as usual, and is then subjected to compression to the required extent to give it the requisite hardness and coherence. In the case of my improved leather this compression causes the bristleroots contained in the adjacent pieces to interlock or penetrate into the pores or part 0f the piece next to them to a greater or less extent, and thus more effectively to unite the skins and add to the coherence and resiliency of the tire.

The tire thus constructed is found to be superior in point of elasticity, imperviousness, and durability to any other leather tire hitherto known.

In the accompanying drawings, Figure l shows a tire arranged vertically to the rim and transversely to the plane of the wheel. Fig. 2 shows a part of a wheel with a tire of my invention arranged vertically to the rim and-longitudinally to the plane of the Wheel. Fig. 3 is a diagram of a tire arranged in layers concentric with the wheel-rim.

In the drawings, d indicates the Wheel, b the rim, and c the leather tire. The wheels and rims may obviously be of any suitable shape or section.

Vhat I claim isl. The herein-described process for preparing leather for leather wheel-tires which consists, first, in partially unhairing pigskin, so as to preserve the bristle-roots, secondly in withdrawing the said skins from the liming process before the commencement of caustic, disintegrating or putrefactive action, and completing process as described by substitutes for lime, thirdly in dividing the said skins into segments, fourthly, in compressing the said segments into the form of a wheeltire under pressure sufficient to cause the bristle-roots to penetrate adjacent layers of material, and fifthly, in injecting waterproofing composition underpressure, substantially as described.

2. In combination with a wheel, a concave metallic rimmultiple layers of compressedpigskin leather arranged in planes perpendicular to the circumference of the wheel, bristle-roots in the said layers interpenetrating adjacent layers, and waterproofing composition forced into the said layers, substantially as described.

3. As a new article of manufacture, a waterproof-leather wheel-tire composed ofmultiple layers of partially-unhaired and antiseptically-tanned pigskin, bristle-roots in said layers uniting adjacent layers, and a waterproofing composition forcibly compressed into the substance of said layers, substantially as described.

In witness whereof I have hereunto set my hand in presence of two witnesses.

JOHN MUIR. llfitnesses:

GEORGE WILLIAM RosE, XV. M. HARRIS.

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